Nucleation crystalline polymer growth

The previous sections dealt primarily with phase transformations and corrosion in materials. Polymers also undergo phase transformations. For example, there are many polymers that utilize nucleation and growth kinetics to transform from amorphous to crystalline polymers. The kinetics of these transformations are very similar, in principle, to the preceding descriptions for glasses, so it is not necessary to duplicate that material here. Polymers also are susceptible to corrosion, but the term degradation is more... 

Crystallization is an inherently time-dependent process the nucleation and growth of crystalline structures, the degree of crystallinity, the phase structure and quality of crystal lamellae, and their connectedness strongly influence the mechanical properties of semi-crystalline polymers. It is for this... 

If nucleation and growth cannot be studied independently, the overall conversion of amorphous into crystalline polymer may be followed with the aid of any technique giving a measure of the degree of crystallinity. For instance, the specific volume may be followed by enclosing the crystallising sample in a dilatometer. It is customary to define the overall rate of crystallisation at a given temperature as the inverse of the time needed to attain... 

The cooling of polymer melt in the presence of a foreign surface which can nucleate crystalline growth inhibits the lateral growth of spherulites. Crystallization occurs This is called transcrystallinity. It can im-... 

The degree of crystallinity and spheralite density of PLA also increased with an increase in the number of branches. This view is not supported by other works in the field. The presence of short chain branches in polyethylene delayed the onset of nucleation and the growth of crystalline stractures. Star-chain branched PA-11 had low crystallization rate because star-branched core and its adjacent chains were unable to crystallize. Methyl groups may still be included in the PE orthorhombic crystal lattice, but with increased methyl group content, polymer gradually looses its ability to crystalUze when the methyl content reaches 20 wt%. If short-chain brarrches increase in size to 1-butane, 1-hexane, 1-octane, the crystallization is even more severely hampered. ... 

For fiber reinforced composites based on semicrystalline matrix, the ultimate properties are determined in part by the crystalline morphology of the polymer matrix, which in turn depends on the rates of nucleation and crystal growth. Therefore, the knowledge and understanding of crystallization mechanisms are crucial for designing the tailored materials or products with the desirable properties. In this section, we would like to introduce the crystallization kinetics of PET/PP MRCs first, and then the crystaUine structures and aggregated morphology will be also presented. 

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